Casey Saup The Ohio State University saup.4@osu.edu https://orcid.org/0000-0002-3718-2958 Mikayla Borton mikayla.borton@colostate.edu https://orcid.org/0000-0001-8037-4253 Amelia Nelson Colorado State University amelia.nelson@colostate.edu https://orcid.org/0000-0003-1759-6587 Robert Danczak robert.danczak@pnnl.gov https://orcid.org/0000-0003-1396-192X Kira Harris The Ohio State University kiraharris@email.arizona.edu https://orcid.org/0000-0003-0342-1022 Rosalie Chu Rosalie.Chu@pnnl.gov https://orcid.org/0000-0001-7428-7647 James Stegen james.stegen@pnnl.gov https://orcid.org/0000-0001-9135-7424 Kenneth Williams khwilliams@lbl.gov https://orcid.org/0000-0002-3568-1155 Audrey Sawyer The Ohio State University sawyer.143@osu.edu https://orcid.org/0000-0001-8174-0542 Michael Wilkins mike.wilkins@colostate.edu https://orcid.org/0000-0002-3595-0853 U.S. DOE > Office of Science > Biological and Environmental Research (BER) http://dx.doi.org/10.13039/100006206 fundingOrganization 2023 Pore water samples were collected from distributed locations around Meander A in East River (Crested Butte, CO, USA) during the summer of 2018. This dataset consists of the characterization of dissolved organic matter using 12 Tesla Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS; in .xml format) analyzed through the Environmental Molecular Sciences Laboratory (EMSL; https://www.pnnl.gov/environmental-molecular-sciences-laboratory). This study aimed to understand organic matter assemblages differ within a streambed with differing geomorphology and the interplay between streambed organic matter and microbiome function. Any published work that utilizes data presented in this dataset should cite the dataset using the DOI number. If using the dataset, please acknowledge the U.S. Department of Energy (DOE) Office of Science (BER) Subsurface Biogeochemical Research (SBR) program, the Environmental Molecular Sciences Laboratory (EMSL), and Worldwide Hydrobiogeochemical Observation Network for Dynamic River Systems (WHONDRS). The publication DOI will be added to this abstract when available. Pore water Hyphorheic mixing FTICR-MS Metabolomics Organic matter River corridor Biogeochemistry Mass spectrometry Metabolite CATEGORICAL:NONE

Nelson, A. R., Sawyer, A. H., Gabor, R. S., Saup, C. M., Bryant, S. R., Harris, K. D., ... & Wilkins, M. J. (2019). Heterogeneity in hyporheic flow, pore water chemistry, and microbial community composition in an alpine streambed. Journal of Geophysical Research: Biogeosciences, 124(11), 3465-3478. https://doi.org/10.1029/2019JG005226Nelson A ; Saup C ; Gabor R ; Bryant S ; Harris K ; Williams K ; Wilkins M ; Sawyer A (2019): Distributed hydrological, chemical, and microbiological measurements around Meander A of East River, Colorado. Seasonal controls on dynamic hyporheic zone redox biogeochemistry, ESS-DIVE repository. Dataset. doi:10.15485/1507800 accessed via https://data.ess-dive.lbl.gov/datasets/doi:10.15485/1507800 on 2023-02-17Saup, C. M., Bryant, S. R., Nelson, A. R., Harris, K. D., Sawyer, A. H., Christensen, J. N., ... & Wilkins, M. J. (2019). Hyporheic zone microbiome assembly is linked to dynamic water mixing patterns in snowmelt‐dominated headwater catchments. Journal of Geophysical Research: Biogeosciences, 124(11), 3269-3280. https://doi.org/10.1029/2019JG005189Nelson, A.R., Toyoda, J., Chu, R.K., Tolic, N., Garayburu-Caruso, V., Saup, C.M., Renteria, L., Wells, J.R., Stegen, J., Wilkins, M.J., Danczak, R.E. (2022). “Implications of sample treatment on characterization of the riverine dissolved organic matter.” Environmental Science: Processes & Impacts. doi: 10.1039/D2EM00044J.Nelson A ; Toyoda J ; Chu R ; Tolic N ; Garayburu-Caruso V ; Saup C ; Renteria L ; Wells J ; Stegen J ; Wilkins M ; Danczak R (2021): East River Surface and Pore Water FTICR-MS Data Associated with “Implications of sample treatment on characterization of the riverine environmental metabolome”. Seasonal controls on dynamic hyporheic zone redox biogeochemistry, ESS-DIVE repository. Dataset. doi:10.15485/1813303 accessed via https://data.ess-dive.lbl.gov/datasets/doi:10.15485/1813303 on 2023-02-17

This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Meander A, East River, Colorado near Crested Butte (coordinates for all locations on EastRiver_FTICR_Metadata.csv) -106.951006981 -106.951006981 38.923540687 38.923540687 2018-08-06 2018-08-13 Michael Wilkins mike.wilkins@colostate.edu https://orcid.org/0000-0002-3595-0853 Seasonal controls on dynamic hyporheic zone redox biogeochemistry Pore water samples were collected from the East River (CO, USA) on a 200-m reach encompassing one meander that lies within the U.S. Department of Energy-supported Lawrence Berkeley National Laboratory’s Watershed Science Focus Area. See Nelson et al. (2019) for more detailed information on sampling efforts (DOIs included). Briefly, pore water samples were collected from their respective depths (metadata csv) using a 0.6 cm diameter, stainless steel pore water sipper with a screen length of 5 cm attached to a syringe (MHE Products, MI, USA). One tubing volume of approximately 30 mL was discarded before sampling and sample was filtered through 0.22 μm Sterivex filters (housings made of Eastar co-polyester; Massachusetts, USA). The 20 mL aliquot for the data presented here was filtered into a pre-combusted amber glass vial and immediately placed in a cooler on ice for transport back to the lab. See publication DOI (to be added following publication) for detailed FTICR-MS methods. The following is a general overview of the FTICR-MS steps: Aqueous samples (NPOC 0.33-0.99 mg C/L) were acidified to pH 2 with 85% phosphoric acid and extracted with PPL cartridges (Bond Elut). For those samples which were not extracted, 250 μL of sample were mixed with 500 μL of LC-MS grade MeOH. A 12 Tesla (12T) Bruker SolariX Fourier transform ion cyclotron resonance mass spectrometer (Bruker, Billerica, MA) located at the Environmental Molecular Sciences Laboratory in Richland, WA was used to collect high-resolution mass spectra of the organic matter found in each sample. A Bruker SolariX electrospray ionization (ESI) source was used in positive and negative modes with applied voltages of +4.4kV and -4.2kV, respectively. Michael Wilkins The Ohio State University, Columbus, OH wilkins.231@osu.edu Principal Investigator Audrey Sawyer Ohio State University sawyer.143@osu.edu Principal Investigator EastRiver_FTICR_MS.zip application/zip